Another manual steering box question

I recently picked up a manual box from a 63 valiant at a pick your part yard. Its in really good shape but sounded a little dry but absolutely no play . For the money i saved im thinking about putting bearings and seals in it . 1st question is firm feel the only co. That sales a kit for our boxes ?
2nd question i have read many posts and the guys here are putting grease in my fsm says to use 90 wt gear oil any thoughts ?